Imaging device for phase difference detection

ABSTRACT

An imaging device includes phase difference detection pixels. The imaging device receives an image formed by an optical system and includes a plurality of pixels that are two-dimensionally arranged. Each of the plurality of pixels include a micro lens; a photoelectric conversion unit positioned below the micro lens; and an optical aperture disposed between the micro lens and the photoelectric conversion unit and that is eccentric with respect to an optical axis of the micro lens, wherein the plurality of pixels of the imaging device output a signal for obtaining phase difference. The imaging device performs phase difference detection on the entire surface of a captured image without addition of pixels.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

This application claims the priority benefit of Korean PatentApplication No. 10-2011-0072078, filed on Jul. 20, 2011, in the KoreanIntellectual Property Office, the disclosure of which is incorporatedherein in its entirety by reference.

BACKGROUND

1. Field

Embodiments relate to an imaging device including phase differencedetection pixels.

2. Description of the Related Art

Devices including phase difference detection pixels that perform phasedifference detection autofocus (AF) by using an imaging device for imageinput have been proposed. Generally, phase difference detection pixelsare added between imaging pixels, and phase difference is detected usingthe added pixels. However, only phase difference detection is performedin an area in which phase difference detection pixels are present, andthe phase difference detection is not performed in any other area. Inaddition, there is a big difference between outputs of phase differencedetection pixels and that of other pixels, and the phase differencedetection pixels are regarded as defect pixels. As a result, the qualityof captured images is deteriorated.

SUMMARY

Embodiments include an imaging device in which phase differencedetection may be performed using entire pixels without addition ofpixels and focal point information (position and direction of a focalpoint) may be obtained therefrom.

According to an embodiment, an imaging device configured to receive animage formed by an optical system includes a plurality of pixels thatare two-dimensionally arranged. Each of the plurality of pixelsincludes: a micro lens; a photoelectric conversion unit positioned belowthe micro lens; and an optical aperture disposed between the micro lensand the photoelectric conversion unit and that is eccentric with respectto an optical axis of the micro lens, wherein the plurality of pixels ofthe imaging device output a signal for obtaining phase difference.

The optical aperture may include a light shielding mask.

The optical aperture may be formed by eccentrically positioning a wirelayer of each of the plurality of pixels.

Each of the plurality of pixels may have an optical aperture thatincludes an optical axis of the micro lens.

Each of the plurality of pixels may have an optical aperture thatincludes an optical axis of the micro lens, or an optical aperture thateither does not contact the optical axis of the micro lens or contactsbut does not include the optical axis.

Each of the plurality of pixels may have an optical aperture that eitherdoes not contact an optical axis of the micro lens or contacts but doesnot include the optical axis.

Each of the plurality of pixels may include a red (R), green (G), orblue (B) color filter.

The G color filter may be disposed in a pixel having a first apertureratio, and the R or B color filter may be disposed in a pixel having asecond aperture ratio.

Each of the plurality of pixels may include a cyan (C), magenta (M), oryellow (Y) color filter.

The color filter may be disposed in a pixel having a first apertureratio, and the color filter may not be disposed in a pixel having asecond aperture ratio that is greater than the first aperture ratio.

The optical aperture may be eccentrically formed in horizontal andvertical directions.

The optical aperture may be eccentrically formed in an inclineddirection and in a direction converse to the inclined direction.

The optical aperture may include a plurality of eccentric opticalapertures so as for a full-aperture to use different lenses.

A focal point detection area having a first aperture ratio may bearranged at a plurality of positions including a center of the imagingdevice, and a focal direction detection area may be arranged at aposition other than the focal point detection area.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages will become more apparent bydescribing in detail exemplary embodiments with reference to theattached drawings in which:

FIG. 1 is a block diagram illustrating a structure of a digital imageprocessing device including an imaging device, according to anembodiment;

FIG. 2 is a diagram for explaining a principle of phase differencepixels by using the imaging device of FIG. 1, according to anembodiment;

FIGS. 3A and 3B are graphs for explaining phase difference of lightreceiving pixels according to FIG. 2, according to an embodiment;

FIG. 4 is a diagram illustrating a structure of pixels constituting ageneral imaging device;

FIG. 5 is a diagram illustrating a structure of pixels constituting aphase difference imaging device of FIG. 1, according to an embodiment;

FIG. 6 is a diagram illustrating a structure of pixels constituting animaging device, according to another embodiment;

FIGS. 7A and 7B are diagrams illustrating a relationship between aposition of masks of phase difference pixels of the imaging device ofFIG. 5 and imaging lenses, according to an embodiment;

FIG. 8 illustrates a general Bayer pattern pixel structure of an imagingdevice;

FIGS. 9A and 9B illustrate phase difference pixels of the imaging deviceof FIGS. 7A and 7B configured in a horizontal direction based on theBayer pattern pixel structure of FIG. 8, according to an embodiment;

FIGS. 10A and 10B illustrate phase difference pixels of the imagingdevice of FIGS. 7A and 7B configured in a vertical direction based onthe Bayer pattern pixel structure of FIG. 8, according to an embodiment;

FIGS. 11A and 11B are diagrams illustrating a relationship between aposition of masks of phase difference pixels and imaging lenses,according to another embodiment;

FIGS. 12A and 12B illustrate phase difference pixels of the imagingdevice of FIGS. 11A and 11B configured in a horizontal direction basedon the Bayer pattern pixel structure of FIG. 8, according to anembodiment;

FIGS. 13A and 13B illustrate phase difference pixels of the imagingdevice of FIGS. 11A and 11B configured in a vertical direction based onthe Bayer pattern pixel structure of FIG. 8, according to an embodiment;

FIGS. 14A and 14B illustrate phase difference pixels of the imagingdevice of FIGS. 7A and 7B configured in horizontal and verticaldirections based on the Bayer pattern pixel structure of FIG. 8,according to an embodiment;

FIG. 15 illustrates a combined configuration of the phase differencepixels of the imaging devices of FIGS. 9A, 9B, 10A, 10B, 13A, 13B, 14A,and 14B, according to an embodiment;

FIG. 16 illustrates a configuration of the phase difference pixels ofthe imaging device of FIGS. 14A and 14B, according to an embodiment;

FIG. 17 illustrates a combined configuration of the phase differencepixels of the imaging devices of FIG. 15, according to anotherembodiment;

FIG. 18 is a diagram for explaining a principle of phase differencepixels with high focal position detection accuracy, according to anembodiment;

FIGS. 19A and 19B are diagrams illustrating a relationship between aposition of masks of phase difference pixels and F2.8 imaging lenses,according to an embodiment;

FIGS. 20A and 20B illustrate phase difference pixels of the imagingdevice of FIGS. 19A and 19B configured in a horizontal direction byusing the F2.8 imaging lenses of FIGS. 19A and 19B, according to anembodiment;

FIG. 21 illustrates a combined configuration of the phase differencepixels of the imaging devices of FIGS. 9A, 9B, 20A, and 20B, accordingto an embodiment;

FIGS. 22A and 22B illustrate the phase difference pixels illustrated inFIGS. 19A and 19B configured in a horizontal direction, according toanother embodiment;

FIGS. 23A and 23B illustrate the phase difference pixels illustrated inFIGS. 19A and 19B configured in a horizontal direction, according toanother embodiment;

FIG. 24 illustrates a combined configuration of the phase differencepixels illustrated in FIGS. 22A, 22B, 23A, and 23B, according to anembodiment;

FIGS. 25A and 25B illustrate the phase difference pixels illustrated inFIGS. 19A and 19B configured in a horizontal direction, according toanother embodiment;

FIGS. 26A and 26B illustrate the phase difference pixels of FIGS. 25Aand 25B configured in a vertical direction, according to an embodiment;

FIG. 27 illustrates a combined configuration of the phase differencepixels of FIGS. 25A, 25B, 26A, and 26B, according to an embodiment;

FIG. 28 illustrates a combined configuration of the phase differencepixels of FIG. 27, according to another embodiment;

FIGS. 29A and 29B illustrate a configuration of the phase differencepixels of FIGS. 25A and 25B, according to another embodiment;

FIGS. 30A and 30B illustrate an MA configuration of phase differencepixels for detecting a focal position by detecting phase difference withrespect to right, upper, left, and lower directions, according to anembodiment;

FIGS. 31A and 31B illustrate an NA configuration of phase differencepixels for detecting a focal position by detecting phase difference withrespect to left, upper, right, and lower directions, according to anembodiment;

FIGS. 32A and 32B illustrate an MB configuration of phase differencepixels for detecting a focal direction by detecting phase differencewith respect to right, upper, left, and lower directions, according toan embodiment;

FIGS. 33A and 33B illustrate an NB configuration of phase differencepixels for detecting a focal direction by detecting phase differencewith respect to left, upper, right, and lower directions, according toan embodiment;

FIG. 34 illustrates a combined configuration of the phase differencepixels of FIGS. 30A, 30B, 31A, 31B, 32A, 32B, 33A, and 33B, according toan embodiment.

DETAILED DESCRIPTION

Particular embodiments will be illustrated in the drawings and describedin detail in the written description; however, this should not beconstrued as limiting, and it is to be appreciated that all changes,equivalents, and substitutes that do not depart from the spirit andtechnical scope are encompassed within the invention as recited in thefollowing claims. In the description, certain detailed explanations ofrelated art are omitted when it is deemed that they may unnecessarilyobscure the essence of the invention as recited in the following claims.

Embodiments will now be described more fully with reference to theaccompanying drawings, in which exemplary embodiments are shown. In thedrawings, like reference numerals denote like elements, and thus adetailed description thereof is provided once.

FIG. 1 is a block diagram illustrating a structure of a digital imageprocessing device 100 including an imaging device 108, according to anembodiment.

Referring to FIG. 1, the digital image processing device 100 and a lensare configured separate from each other, but the imaging device 108 isconfigured in an integrated manner with the digital image processingdevice 100. In addition, the digital image processing device 100including the imaging device 108 may perform phase difference autofocus(AF) and contrast AF.

The digital image processing device 100 includes an imaging lens 101including a focus lens 102. The digital image processing device 100 hasfocus detection capability, and thus the focus lens 102 may be operated.The imaging lens 101 includes a lens operation unit 103 that operatesthe focus lens 102, a lens position detection unit 104 that detects aposition of the focus lens 102, and a lens control unit 105 thatcontrols the focus lens 102. The lens control unit 105 transmitsinformation on focus detection to a CPU 106 of the digital imageprocessing device 100.

The digital image processing device 100 includes the imaging device 108,and thus captures light that is incident on and transmitted through theimaging lens 101, thereby generating an image signal. The imaging device108 may include a plurality of photoelectric conversion units (notshown) arranged in a matrix form and a transfer path (not shown) thattransfers charges from the photoelectric conversion units, therebyreading an image signal.

An imaging device control unit 107 generates a timing signal, therebycontrolling the imaging device 108 to capture an image. In addition, theimaging device control unit 107 sequentially reads out image signalswhen accumulation of charges on each of a plurality of scan lines isterminated.

The read-out image signals are converted to digital image signals by anA/D conversion unit 110 via an analogue signal processing unit 109, andthen input to an image input controller 111 and processed therein.

The digital image signals input to the image input controller 111 aresubjected to auto white balance (AWB), auto exposure (AE) and AFcalculations respectively performed by an AWB detection unit 116, an AEdetection unit 117, and an AF detection unit 118. The AF detection unit118 outputs a detection value with respect to a contrast value duringcontrast AF, and outputs pixel information to the CPU 106 during phasedifference AF, thereby allowing phase difference calculation to beperformed in the CPU 106. The phase difference calculation performed bythe CPU 106 may be obtained by calculating a correlation between aplurality of pixel row signals. As a result of the phase differencecalculation, a position or direction of a focal point may be obtained.

The image signals are also stored in a synchronous dynamic random accessmemory 119 (SDRAM), that is, a temporary memory. A digital signalprocessing unit 112 performs a series of image signal processingoperations such as gamma correction to create a displayable live viewimage or captured image. A compression/decompression unit 113 compressesan image signal in a JPEG compression format or an H.264 compressionformat or decompresses the image signal when image signal processing isperformed. An image file including the image signal compressed in thecompression/decompression unit 113 is transmitted to a memory card 122via a media controller 121 to be stored therein.

In FIG. 1, the CPU 106, the analogue signal processing unit 109, the A/Dconversion unit 110, the image input controller 111, the digital signalprocessing unit 112, the compression/decompression unit 113, a videocontroller 114, the AWB detection unit 116, the AE detection unit 117,the AF detection unit 118, and the media controller 121 may be referredto as an image processing circuit. The image processing circuit may becommonly referred to as an integrated circuit (IC) and the CPU 106 maybe the image processing circuit.

Image information for display is stored in a video RAM 120 (VRAM), andan image is displayed on an LCD 115 via the video encoder 114. The CPU106 controls overall operations of each unit of the digital imageprocessing device 100. An electrically erasable programmable read-onlymemory (EEPROM) 123 stores and maintains information for correctingdefects of pixels of the imaging device 108 or adjustment information onthe pixel defects. A manipulation unit 124 is a unit through whichvarious commands of a user are input to manipulate the digital imageprocessing device 100. The manipulation unit 124 may include variousbuttons such as a shutter-release button, a main button, a mode dial, amenu button, or the like.

FIG. 2 is a diagram for explaining a principle of phase differencepixels by using the imaging device 108 of FIG. 1, according to anembodiment.

Light of a subject that has transmitted through an imaging lens 11transmits through a micro lens array 14 to be incident onto lightreceiving pixels R(15) and L(16). Masks 17 and 18 for restricting pupils12 and 13 of the imaging lens 11, or restricted optical apertures, arerespectively formed in portions of the light receiving pixels R(15) andL(16). Among the pupils 12 and 13 of the imaging lens 11, light from thepupil 12 above an optical axis 10 of the imaging lens 11 is incidentonto the light receiving pixel L(16), and light from the pupil 13 belowthe optical axis 10 of the imaging lens 11 is incident onto the lightreceiving pixel R(15). Light that is reverse transmitted to the pupils12 and 13 by the micro lens array 14 is received by the light receivingpixels R(15) and L(16) by the masks 17 and 18 or the optical apertures,which is referred to as pupil division.

FIGS. 3A and 3B are graphs for explaining phase difference of lightreceiving pixels according to FIG. 2, according to an embodiment.Continuous output of the light receiving pixels R(15) and L(16) by pupildivision by the micro lens array 14 is illustrated in FIGS. 3A and 3B.In FIGS. 3A and 3B, a horizontal axis denotes positions of the lightreceiving pixels R(15) and L(16), and a vertical axis denotes outputvalues of the light receiving pixels R(15) and L(16). Referring to FIGS.3A and 3B, graphs showing output of the light receiving pixels R(15) andL(16) exhibit the same shape, but exhibit different phases with respectto position. This is due to image formation positions of light from theeccentrically formed pupils 12 and 13 of the imaging lens 11 beingdifferent from each other. Thus, when focus points of light from theeccentrically formed pupils 12 and 13 are inconsistent with each other,the light receiving pixels R(15) and L(16) exhibit an output phasedifference, as illustrated in FIG. 3A. On the other hand, when focuspoints of light from the eccentric pupils 12 and 13 are consistent witheach other, images are formed at the same position as illustrated inFIG. 3B. In addition, a direction of focus may be determined from thefocus difference. A front-focusing indicates that an object is in afront focus state, and the front-focusing is illustrated in FIG. 3A.Referring to FIG. 3A, the phase of the output of the light receivingpixel R(15) is shifted further to the left than that in the focusedphase, and the phase of the output of the light receiving pixel L(16) isshifted further to the right than that in the focused phase. Incontrast, a back-focusing indicates that an object is in a back focusstate. In this case, the phase of the output of the light receivingpixel R(15) is shifted further to the right than that in the focusedphase, and the phase of the output of the light receiving pixel L(16) isshifted further to the left than that in the focused phase. The shiftamount between the phases of the light receiving pixels R(15) and L(16)may be converted to a deviation amount between the focuses.

FIG. 4 is a diagram illustrating a structure of pixels constituting ageneral imaging device.

Referring to FIG. 4, two pixels are illustrated. The two pixels includemicro lenses 21, a surface layer 22, a color filter layer 23, a wirelayer 24, photodiode layers 25, and a substrate layer 26. Aphotoelectric conversion unit of each pixel may include at leastportions of the wire layer 24 and the photodiode layer 25.

Light from a subject enters the photodiode layer 25 of each pixel viathe micro lenses 21, and a photodiode in the photodiode layer 25 of eachpixel generates charges that serve as pixel information. The generatedcharges are released through the wire layer 24. Such incident light froma subject is all light that has transmitted through an exit pupil of animaging lens, and luminance information corresponding to a subjectposition may be obtained corresponding to a pixel position. In general,the color filter layer 23 may be a layer including pixels of red (R),green (G), and blue (B). Also, the color filter layer 23 may includepixels of cyan (C), magenta (M), and yellow (Y).

FIG. 5 is a diagram illustrating a structure of pixels constituting thephase difference imaging device 108 of FIG. 1, according to anembodiment. An exemplary embodiment of phase difference pixels obtainedby forming masks 27 and 28 in optical apertures of the imaging deviceillustrated in FIG. 4 so as to obtain R and L signals as illustrated inFIGS. 3A and 3B is illustrated in FIG. 5.

Referring to FIG. 5, a mask 27 for R pixels and a mask 28 for L pixelsare each interposed between the micro lenses 21 and the photodiodelayers 25, but the positions of the masks 27 and 28 are not limited tothe example illustrated in FIG. 5. For example, the masks 27 and 28 maybe interposed somewhere else therebetween. In FIG. 5, optical axes ofthe micro lenses 21 are each represented by a dashed dotted line, andpaths through which light is incident from the micro lenses 21 are eachrepresented by a broken line. The amounts of light incident on thephotodiode layers 25 are restricted by 50% by the masks 27 and 28,respectively, when the masks 27 and 28 correspond to the optical axes ofthe micro lenses 21.

FIG. 6 is a diagram illustrating a structure of pixels constituting theimaging device 108, according to another embodiment. In this embodiment,instead of formation of masks in the optical apertures of the imagingdevice 108, the wire layer 24 is disposed on one side of each pixel andthus a mask effect may be obtained.

When an imaging device is designed, an aperture ratio in each of pixelsis generally restricted to about 40% because each pixel includes thewire layer 24. In FIG. 6, the wire layer 24 is disposed in an endportion of each pixel, thereby completing formation of pixels R and Lserving as phase difference pixels. In this embodiment, however, thewire layer 24 needs to be configured for a pixel R and a pixel L. Thus,in an overall configuration, the wire layer 24 is disposed having azigzag configuration.

Hereinafter, for convenience of explanation, an actual aperture ratio ofpixels of 40% will be described as an aperture ratio of 100%. Forexample, an aperture ratio of 70% in the following description indicatesan actual aperture ratio of 28%.

FIGS. 7A and 7B are diagrams illustrating a relationship between aposition of masks of phase difference pixels of the imaging device ofFIG. 5 and imaging lenses, according to an embodiment.

FIG. 7A illustrates an imaging lens 31, an R pixel 33 of the imagingdevice of FIG. 5, a top view of a mask 34, and a pupil 32 that is on theimaging lens 31 and incident on the mask 34. FIG. 7B illustrates animaging lens 36, an L pixel 38 of the imaging device of FIG. 5, a topview of a mask 39, and a pupil 37 that is on the imaging lens 36 andincident on the mask 39.

Light that has transmitted through the pupil 32 of the imaging lens 31or the pupil 37 of the imaging lens 36 is incident on the R pixel 33 orthe L pixel 38, respectively. The masks 34 and 39 each have an apertureratio of about 50% with respect to the optical axes of the imaginglenses 31 and 36. In other words, the R and L pixels 33 and 38 each havean aperture ratio of about 50% with respect to the optical axes of theimaging lenses 31 and 36, each optical aperture of which does notcontact the optical axes or contacts but does not include the opticalaxes.

The R pixel 33 and the L pixel 38 illustrated in FIGS. 7A and 7B may notnecessarily be arranged adjacent to each other. In addition, FIGS. 7Aand 7B illustrate a configuration of pixels arranged in vicinity of theoptical axes of the imaging lenses 31 and 36. If pixels are arrangedfurther away from the optical axes of the imaging lenses 31 and 36, tocorrect the cost law, positions of the optical axes of the imaginglenses 31 and 36 and the masks 34 and 39 are shifted in an externaldirection of a screen.

FIG. 8 illustrates a general Bayer pattern pixel structure of an imagingdevice.

Referring to FIG. 8, color filters of three colors, i.e., red (R), green(G), and blue (B), are arranged and 4 pixels are configured as a singleunit. In this regard, two G pixels are arranged in the unit.

FIGS. 9A and 9B illustrate phase difference pixels of the imaging deviceof FIGS. 7A and 7B configured in a horizontal direction based on theBayer pattern pixel structure of FIG. 8, according to an embodiment.

FIG. 9A illustrates a configuration of a color filter and the R pixel 33and a configuration of a color filter and the L pixel 38, and FIG. 9Billustrates arrangements of the masks 34 and 39. In FIG. 9A, RLa denotesthat a mask for the L pixel 38 is formed in a red (R) color filter.

In FIGS. 9A and 9B, the R and L pixels 33 and 38 each have an apertureratio of about 50% with respect to the optical axes of the imaginglenses 31 and 36, each optical aperture of which does not contact theoptical axes or contacts but does not include the optical axes. In thisregard, the masks 34 and 39 illustrated in FIG. 9B are referred to as an“A-type mask” for convenience of explanation, and thus a configurationof phase difference pixels in a horizontal direction is referred to asHA.

In FIGS. 9A and 9B, L pixels are arranged in a first row 41 and a secondrow 42, and R pixels are arranged in a third row 43 and a fourth row 44.Pixel row signals of each pixel of the first row 41 and the second row42 or a sum (binning output) of pixel row signals of each L pixel of thefirst row 41 and each pixel of the second row 42, and pixel row signalsof each pixel of the third row 43 and the fourth row 44 or a sum(binning output) of pixel row signals of each pixel of the third row 43and the fourth row 44 are obtained as illustrated in FIGS. 3A and 3B tocalculate a phase difference between the R and L pixels. In this regard,areas for obtaining binning output are not limited to the above example,and binning output with respect to wider areas may be performed. Inaddition, binning output may be performed on pixels of the same color.When binning output of pixels of the same color is obtained, the binningoutput may be used in a live view image. The pixel row signals areobtained as a line image in a horizontal direction. Thus, an image witha contrast change in a horizontal direction may be detected.

As described above, the HA is composed of pixels having an apertureratio of about 50% with respect to the optical axes of the imaginglenses 31 and 36, each optical aperture of which does not contact theoptical axes or contacts but does not include the optical axes, and thuscrosstalk between adjacent pixels does not occur and a position of afocal point in a horizontal direction of a subject may be obtained fromthe phase difference information.

FIGS. 10A and 10B illustrate phase difference pixels of the imagingdevice of FIGS. 7A and 7B configured in a vertical direction based onthe Bayer pattern pixel structure of FIG. 8, according to an embodiment.

FIG. 10A illustrates a configuration of a color filter and the R pixel33 and a configuration of a color filter and the L pixel 38, and FIG.10B illustrates arrangements of the masks 34 and 39.

In FIGS. 10A and 10B, the R and L pixels 33 and 38 each have an apertureratio of about 50% with respect to the optical axes of the imaginglenses 31 and 36, each optical aperture of which does not contact theoptical axes or contacts but does not include the optical axes. In thisregard, the masks 34 and 39 illustrated in FIG. 10B are referred to asan “A-type mask” for convenience of explanation, and thus aconfiguration of phase difference pixels in a vertical direction isreferred to as VA.

In FIGS. 10A and 10B, L pixels are arranged in a first row 51 and asecond row 52, and R pixels are arranged in a third row 53 and a fourthrow 54. Pixel row signals of each pixel of the first row 51 and thesecond row 52 or a sum (binning output) of pixel row signals of each Lpixel of the first row 51 and each pixel of the second row 52, and pixelrow signals of each pixel of the third row 53 and the fourth row 54 or asum (binning output) of pixel row signals of each pixel of the third row53 and the fourth row 54 are obtained as illustrated in FIGS. 3A and 3Bto calculate a phase difference between the R and L pixels.

The pixel row signals are obtained as a line image in a verticaldirection. The pixel row signals of the VA may be used to detect animage with a contrast change in a vertical direction, and thus aposition of a focal point in a vertical direction of a subject may beobtained from the phase difference information.

FIGS. 11A and 11B are diagrams illustrating a relationship between aposition of masks of phase difference pixels and imaging lenses,according to another embodiment.

FIG. 11A illustrates an imaging lens 61, an R pixel 63 of the imagingdevice of FIG. 5, a top view of a mask 64, and a pupil 62 that is on theimaging lens 61 and incident on the mask 64. FIG. 11B illustrates animaging lens 66, an L pixel 68 of the imaging device of FIG. 5, a topview of a mask 69, and a pupil 67 that is on the imaging lens 66 andincident on the mask 69.

Light that has transmitted through the pupil 62 of the imaging lens 61and light that has transmitted through the pupil 67 of the imaging lens66 are respectively incident on the R pixel 63 and the L pixel 68. Whilethe masks 34 and 39 are respectively positioned to allow the R and Lpixels 33 and 38 of the embodiment of FIGS. 7A and 7B to have anaperture ratio of 50% with respect to the optical axes, the masks 64 and69 are respectively positioned to allow the R and L pixels 63 and 68 tohave an aperture ratio of 50% or greater with respect to the opticalaxes, for example, 75%. In other words, in this embodiment, the R pixel63 has an aperture ratio of 50% or greater with respect to the opticalaxis of the imaging lens 61, an optical aperture of which includes theoptical axis, and the L pixel 68 has an aperture ratio of 50% or greaterwith respect to the optical axis of the imaging lens 66, an opticalaperture of which includes the optical axis. The optical aperture of theR pixel 63 is centered to the right of the optical axis of the imaginglens 61, and the optical aperture of the L pixel 68 is centered to theleft of the optical axis of the imaging lens 66.

In the R and L pixels 33 and 38 of FIGS. 7A and 7B, there is nooverlapped portion between the pupils 32 and 37, and thus phasedifference information thereof does not overlap each other, resulting ina relatively small autofocus (AF) error. On the other hand, darkerimages are obtained as compared with the R and L pixels 63 and 68 ofFIGS. 11A and 11B. In contrast, in the R and L pixels 63 and 68 of FIGS.11A and 11B, there is an overlapped portion between the pupils 62 and67, and thus phase difference information thereof overlaps each other,resulting in a relatively large AF error. On the other hand, brighterimages are obtained as compared with the R and L pixels 33 and 38 ofFIGS. 7A and 7B.

FIGS. 12A and 12B illustrate phase difference pixels of the imagingdevice of FIGS. 11A and 11B configured in a horizontal direction basedon the Bayer pattern pixel structure of FIG. 8, according to anembodiment.

FIG. 12A illustrates a configuration of a color filter and the R pixel63 and a configuration of a color filter and the L pixel 68, and FIG.12B illustrates arrangements of the masks 64 and 69.

While the R and L pixels illustrated in FIGS. 9A and 9B each have anaperture ratio of about 50% with respect to the optical axes of theimaging lenses 31 and 36, and the optical aperture of each pixel doesnot contact the optical axes or contacts but does not include theoptical axes, the R and L pixels of FIGS. 12A and 12B each have anaperture ratio of about 75% with respect to the optical axes of theimaging lenses 61 and 66, and the optical aperture of each pixelincludes the optical axes.

In this regard, the masks 64 and 69 are referred to as a “B-type mask”for convenience of explanation, and thus a configuration of phasedifference pixels in a horizontal direction may be referred to as HB.

In FIGS. 12A and 12B, L pixels are arranged in a first row 71 and asecond row 72, and R pixels are arranged in a third row 73 and a fourthrow 74. Pixel row signals of each pixel of the first row 71 and thesecond row 72 or a sum (binning output) of pixel row signals of each Lpixel of the first row 71 and each pixel of the second row 72, and pixelrow signals of each pixel of the third row 73 and the fourth row 74 or asum (binning output) of pixel row signals of each pixel of the third row73 and the fourth row 74 are obtained as illustrated in FIGS. 3A and 3Bto calculate a phase difference between the R and L pixels.

With respect to the HB of FIGS. 12A and 12B, the optical apertures ofthe HB are sufficiently big that images may be satisfactorily displayedby the imaging device. However, when phase difference detection isperformed on the HB, the optical apertures of the HB each include theoptical axes of the imaging lenses, and thus crosstalk between adjacentpixels occurs. In other words, L pixel information is included in shiftinformation by the R pixels, and thus transverse shift information isincluded therein. Thus, it is difficult to obtain information on focalpoint position detection from phase difference information that may beobtained from the HB, but a focal direction of a subject may be obtainedtherefrom.

FIGS. 13A and 13B illustrate phase difference pixels of the imagingdevice of FIGS. 11A and 11B configured in a vertical direction based onthe Bayer pattern pixel structure of FIG. 8, according to an embodiment.

FIG. 13A illustrates a configuration of a color filter and the R pixel63 and a configuration of a color filter and the L pixel 68, and FIG.13B illustrates arrangements of the masks 64 and 69. In FIG. 13A, RLbdenotes that a mask for the L pixel 68 is formed in a red (R) colorfilter.

While the R and L pixels illustrated in FIGS. 9A and 9B each have anaperture ratio of about 50% with respect to the optical axes of theimaging lenses 31 and 36, and the optical aperture of each pixel doesnot contact the optical axes or contacts but does not include theoptical axes, the R and L pixels of FIGS. 13A and 13B each have anaperture ratio of about 75% with respect to the optical axes of theimaging lens 61 and 66, and the optical aperture of each pixel includesthe optical axes.

In this regard, the masks 64 and 69 are referred to as a “B-type mask”for convenience of explanation, and thus a configuration of phasedifference pixels in a vertical direction may be referred to as VB.

In FIGS. 13A and 13B, L pixels are arranged in a first row 81 and asecond row 82, and R pixels are arranged in a third row 83 and a fourthrow 84. Pixel row signals of each pixel of the first row 81 and thesecond row 82 or a sum (binning output) of pixel row signals of each Lpixel of the first row 81 and each pixel of the second row 82, and pixelrow signals of each pixel of the third row 83 and the fourth row 84 or asum (binning output) of pixel row signals of each pixel of the third row83 and the fourth row 84 are obtained as illustrated in FIGS. 3A and 3Bto calculate a phase difference between the R and L pixels.

Phase difference information that may be obtained from the VB may beused to obtain a focal direction of a subject, like the HB of FIGS. 12Aand 12B.

FIGS. 14A and 14B illustrate phase difference pixels of the imagingdevice of FIGS. 7A and 7B configured in horizontal and verticaldirections based on the Bayer pattern pixel structure of FIG. 8,according to an embodiment.

The R and L pixels each have an aperture ratio of 50%, and thus a focaldirection may be obtained. A configuration of phase difference pixels inhorizontal and vertical directions is referred to as HVA. In the HVAconfiguration, G pixels that are greater in number than R and B pixelsare used as a detection pixel in horizontal and vertical directions.

FIG. 15 illustrates a combined configuration of the phase differencepixels of the imaging devices of FIGS. 9A, 9B, 10A, 10B, 13A, 13B, 14A,and 14B, according to an embodiment.

Actually, an imaging device may be, for example, a 14.6M pixel imagingdevice having a pixel configuration in which 4670 pixels are arranged ina horizontal direction and 3100 pixels are arranged in a verticaldirection. In this embodiment, however, smaller pixels are arranged forexplanation in diagram form.

Referring to FIG. 15, HAs and VAs are arranged at a center area of animaging device, and HVAs are arranged where HAs and VAs cross eachother. VBs are arranged at left and right regions of the center area,and HBs are arranged in the vicinity of the center area other than theareas where the HAs, the VAs, and the HVAs are arranged. In this regard,the VAs are arranged around the HBs.

The arrangement of the HAs and HBs at the center area of the imagingdevice, which is an optical condition for pupils of the imaging device,is for preventing a vignetting phenomenon. For example, a lens with anaperture of F6.7 or less may obtain high focal position detectionaccuracy because an optical vignetting phenomenon does not occur. Sincethe optical vignetting phenomenon occurs at an area other than thecenter area of the imaging device, HBs and VBs for focal directiondetection, which do not cause problems in terms of density, arearranged. Since the optical vignetting phenomenon increases according toa distance from an optical axis of an imaging lens and it is desirablethat R and L pixels are relatively symmetrically arranged in spite ofthe occurrence of the vignetting phenomenon, the HBs are arranged at thecenter area and upper and lower areas of the imaging device and the VBsare arranged at left and right areas of the imaging device. Furthermore,in an actual imaging device, VAs are arranged in the HB configurationinstead of HAs.

In imaging devices to be described later, phase difference pixels forfocal position detection may also be discretely arranged in aconfiguration of phase difference pixels for focal direction detection,such as HB pixels or VB pixels.

In addition, in the digital image processing device 100, HAs and VAs forfocal position detection are primarily used during AF, and HBs and VBsfor focal direction detection are used in an auxiliary manner.

FIG. 16 illustrates a configuration of the phase difference pixels ofthe imaging device of FIGS. 14A and 14B, according to an embodiment.

Referring to FIG. 16, HAs are arranged at a center area of an imagingdevice, and VAs are arranged at an area other than the center area.

The pixels of the imaging device of FIG. 6 in which the wire layers aredisposed in a zigzag configuration may have the pixel configuration ofFIG. 16. The imaging device may have the same image quality as that of ageneral imaging device, and thus a focal position may be detected usingall the pixels at once. In this regard, the wire layers of the R and Lpixels are disposed in a zigzag configuration.

FIG. 17 illustrates a combined configuration of the phase differencepixels of the imaging devices of FIG. 15, according to anotherembodiment.

Referring to FIG. 17, the pixels are configured in such a manner thatdetection in horizontal and vertical directions is performed in eacharea of the imaging device. Multi-point detection may be performed atnine points composed of HAs, VAs, HVAs, and HBs arranged at a centralarea of an imaging device.

A detailed description of the imaging device for phase differencedetection including an imaging lens with an aperture of F6.7 or less hasbeen provided. A bright imaging lens has decreased focal positiondetection accuracy. With respect to a lens with an aperture of more thanF2.8, the imaging device includes phase difference pixels with highfocal position detection accuracy.

FIG. 18 is a diagram for explaining a principle of phase differencepixels with high focal position detection accuracy, according to anembodiment.

Referring to FIG. 18, positions of an imaging lens and exit pupils ofthe imaging lens are illustrated as in FIG. 2. In FIG. 18, an exit pupil81 for F2.8 of the imaging lens, a micro lens 82, an exit pupil 83 forF6.7, a pupil 86 for a phase difference R pixel in the exit pupil 83 forF6.7, a pupil 85 for a phase difference L pixel in the exit pupil 83 forF6.7, a pupil 87 for a phase difference R pixel in the exit pupil 81 forF2.8, and a pupil 84 for a phase difference L pixel in the exit pupil 81for F2.8 are illustrated.

The pupils 84 and 87 for F2.8 are positioned at a distance from anoptical axis of the imaging lens. In this case, an angle of lightincident on phase difference pixels increases, and when a focal point ofthe light is changed, there is a big change in a position of imageformation. Thus, in such a configuration in which an incident angle oflight increases, a phase difference change is detected at a high level,and thus focal position detection accuracy is high.

FIGS. 19A and 19B are diagrams illustrating a relationship between aposition of masks of phase difference pixels and imaging lenses forF2.8, according to an embodiment.

FIG. 19A illustrates an imaging lens 91, an R pixel 93, a top view of amask 94, and a pupil 92 that is on the imaging lens 91 and incident onthe mask 94. FIG. 19B illustrates an imaging lens 96, an L pixel 98, atop view of a mask 99, and a pupil 97 that is on the imaging lens 96 andincident on the mask 99.

Light that has transmitted through the pupil 92 of the imaging lens 91or the pupil 97 of the imaging lens 96 is incident on the R pixel 93 orthe L pixel 98, respectively. While the masks 34 and 39 illustrated inFIGS. 7A and 7B are respectively positioned to allow the R and L pixels33 and 38 to have an aperture ratio of 50% with respect to the opticalaxes, the masks 94 and 99 illustrated in FIGS. 19A and 19B arerespectively positioned to allow the R and L pixels 93 and 98 to have anaperture ratio of 25% with respect to optical axes of the imaging lenses91 and 96. In this regard, optical apertures of the R and L pixels 93and 98 are respectively positioned at a distance further from theoptical axes of the imaging lenses 91 and 96, as compared to pixels forF6.7. Furthermore, when the size of pixels increases, optical aperturesof the pixels are not made smaller in size, but the optical aperturesmay be positioned at a distance further from an optical axis of animaging lens.

FIGS. 20A and 20B illustrate phase difference pixels of the imagingdevice of FIGS. 19A and 19B configured in a horizontal direction byusing the F2.8 imaging lenses of FIGS. 19A and 19B, according to anembodiment.

FIG. 20A illustrates a configuration of a color filter and the R pixel93 and a configuration of a color filter and the L pixel 98, and FIG.20B illustrates arrangements of the masks 94 and 99.

Referring to FIGS. 20A and 20B, the R and L pixels 93 and 98 each havean aperture ratio of about 25%, each optical aperture of which does notinclude or contact the optical axes of the imaging lenses 91 and 96, andthe optical apertures of the R and L pixels 93 and 98 are respectivelypositioned at a distance from the optical axes of the imaging lenses 91and 96. A configuration of phase difference pixels in a horizontaldirection as illustrated in FIGS. 20A and 20B is referred to as HA25.

Phase difference information that may be obtained from HA25 is focalposition detection information, and focal position detection informationmay be obtained with high accuracy. Although not illustrated in FIGS.20A and 20B, phase difference pixels may also be configured in avertical direction, and such a configuration is referred to as VA25.

FIG. 21 illustrates a combined configuration of the phase differencepixels of the imaging devices of FIGS. 9A, 9B, 20A, and 20B, accordingto an embodiment.

Referring to FIG. 21, a plurality of HA25s are arranged at a centralarea of an imaging device, and a plurality of VA25s are arranged onupper and lower sides of the central area. Although not illustrated inFIG. 21, HAs are interposed between the HA25s and the VA25s. Theplurality of HA25s may be arranged at the central area of the imagingdevice if a lens system that is brighter than an F2.8 lens is used,while the HAs may be arranged if a lens system using other lenses isused.

HAs are arranged on upper and lower sides of the area in which theplurality of VA25s are arranged, and VAs are arranged on left and rightsides of the areas in which the plurality of VA25s, the plurality ofHA25s, and the HAs are arranged. In addition, HBs are arranged on upperand lower sides of the areas in which the HAs and the VAs are arranged,and VBs are arranged on left and right sides of the areas in which theHBs and the VAs are arranged.

In other words, FIG. 21 illustrates a configuration of F2.8 and F6.7phase difference pixels for focal position detection arranged at acentral area of an imaging device, a configuration of F6.7 phasedifference pixels for focal position detection arranged at an outer sideof the central area, and a configuration of phase difference pixels forfocal direction detection arranged at an outermost side of the centralarea.

FIGS. 22A and 22B illustrate the phase difference pixels illustrated inFIGS. 19A and 19B configured in a horizontal direction, according toanother embodiment.

FIG. 22A illustrates a configuration of a color filter and the R pixel93 and a configuration of a color filter and the L pixel 98, and FIG.22B illustrates arrangements of the masks 94 and 99.

In FIGS. 22A and 22B, phase difference pixels for focal directiondetection configured to have an aperture ratio of 70% are illustrated,and such a configuration is referred to as HB70. Although notillustrated in FIGS. 22A and 22B, phase difference pixels may also beconfigured in a vertical direction, and such a configuration is referredto as VB70.

FIGS. 23A and 23B illustrate the phase difference pixels illustrated inFIGS. 19A and 19B configured in a horizontal direction, according toanother embodiment.

FIG. 23A illustrates a configuration of a color filter and the R pixel93 and a configuration of a color filter and the L pixel 98, and FIG.23B illustrates arrangements of the masks 94 and 99.

In FIGS. 23A and 23B, phase difference pixels for focal directiondetection configured to have an aperture ratio of 85% are illustrated,and such a configuration is referred to as HB85. Although notillustrated in FIGS. 23A and 23B, phase difference pixels may also beconfigured in a vertical direction, and such a configuration is referredto as VB85.

FIG. 24 illustrates a combined configuration of the phase differencepixels illustrated in FIGS. 22A, 22B, 23A, and 23B, according to anembodiment.

Referring to FIG. 24, HAs are arranged at a central area of an imagingdevice, and the HAs are also arranged at a left upper side, a rightupper side, a left lower side, and a right lower side of the centralarea. A plurality of HB70s are arranged around the areas in which theHAs are arranged. VAs are arranged on a left side, a right side, anupper side, and a lower side of the central area, a plurality of VB70sare arranged therearound, a plurality of HB85s are arranged between theareas in which the plurality of HB70s and the plurality of VB70s arearranged, and a plurality of VB85s are arranged on left and right sidesof the areas in which the plurality of HB85s, the plurality of HB70s,and a plurality of VB70s are arranged.

Such a configuration may be made considering the quality of capturedimages, and made to improve an aperture ratio of edge regions. Animaging device including such a configuration has an effect ofcorrecting shading by an imaging lens, and may exhibit a focal positiondetection ability and increased quality of images.

FIGS. 25A and 25B illustrate the phase difference pixels illustrated inFIGS. 19A and 19B configured in a horizontal direction, according toanother embodiment.

FIG. 25A illustrates a configuration of a color filter and the R pixel93 and a configuration of a color filter and the L pixel 98, and FIG.25B illustrates arrangements of the masks 94 and 99. In FIG. 25A, only Gpixels are configured as phase difference pixels for focal positiondetection, and R and B pixels are configured as phase difference pixelsfor focal direction detection. Such a configuration is referred to asHC. Although the G pixels have a smaller aperture ratio than the R and Bpixels, the number of G pixels is twice that of either of the R and Bpixels, and thus degradation of image quality may not occur.

FIGS. 26A and 26B illustrate the phase difference pixels of FIGS. 25Aand 25B configured in a vertical direction, according to an embodiment.FIG. 26A illustrates a configuration of a color filter and the R pixel93 and a configuration of a color filter and the L pixel 98, and FIG.26B illustrates arrangements of the masks 94 and 99. Such aconfiguration is referred to as VC.

FIG. 27 illustrates a combined configuration of the phase differencepixels of FIGS. 25A, 25B, 26A, and 26B, according to an embodiment.

Such a configuration in FIG. 27 may be made considering the quality ofcaptured images rather than considering an imaging device itself. HAsare arranged at nine areas including a central area of an imagingdevice, HAs and a plurality of HA25s are both arranged at the centralarea, HCs are arranged between the areas in which the HAs are arranged,and VCs are arranged at 12 areas on left and right sides of the areas inwhich the HAs are arranged. This is a basic configuration. VBs arearranged between the areas in which the HAs and the VCs are arranged.HBs are arranged on upper and lower sides of the basic configuration,and VBs are arranged on left and right sides of the basic configuration.

The configuration of FIG. 27 may be made for detecting multifocal pointscorresponding to several subjects, and an imaging device including sucha configuration may have good image quality.

FIG. 28 illustrates a combined configuration of the phase differencepixels of FIG. 27, according to another embodiment.

HCs are arranged at a central area and HCs are further arranged inmulti-lines on upper and lower sides of the central area, and VCs arearranged in multi-lines where the HCs and the VCs cross each other. HBsare arranged between the areas in which the HCs and the VCs arearranged. VBs are arranged on outermost left and right sides of theimaging device. An imaging device having such a configuration may set afocal point detection area at any position by setting multifocal pointdetection scores using software and thus may be used widely.

FIGS. 29A and 29B illustrate a configuration of the phase differencepixels of FIGS. 25A and 25B, according to another embodiment.

Referring to FIGS. 29A and 29B, one of the G pixels in the Bayer patternpixel structure is replaced by a white (W) pixel. In other words, one ofthe two G pixels of the Bayer pattern pixel structure is removed. The Wpixels are configured as phase difference pixels in a horizontaldirection for focal position detection, and R, G, and B pixels areconfigured as phase difference pixels in a horizontal direction forfocal direction detection. The configuration of the imaging deviceillustrated in FIGS. 29A and 29B is referred to as HAW. Although notillustrated in FIGS. 29A and 29B, phase difference pixels may beconfigured in a vertical direction, and such a configuration is referredto as VAW. In addition, the imaging device may have a configuration inwhich the HCs and the VCs of FIGS. 27 and 28 are replaced by HAWs andVAWs.

The configuration of phase difference pixels described above is used todetect phase difference in a horizontal or vertical direction. However,phase difference pixels may be arranged in a concentric circle withrespect to an optical axis of an imaging lens to detect phasedifference. By using such a configuration, symmetry of a subject may beeasily obtained. In this case, focal position detection error withrespect to light from a pupil of an imaging lens is small. In addition,with respect to a subject with contrast that is distributed slantingly,there is a possibility of error occurrence in focal position detectionby error occurrence in fabrication of a mask formed in an opticalaperture of a pixel. FIGS. 30A through 33B illustrate configurations ofphase difference pixels arranged in an inclined direction, wherein phasedifference information may be detected with respect to the inclineddirection, according to various embodiments.

FIGS. 30A and 30B illustrate an MA configuration of phase differencepixels for detecting a focal position by detecting phase difference withrespect to right, upper, left, and lower directions, according to anembodiment. MA denotes a D pixel row that corresponds to the L pixelillustrated in FIG. 2. Phase difference calculation is performed usingGDa, RDa, GDa, BDa, GDa, RDa, GDa, . . . , and phase differencecalculation is performed using BUa, GUa, RUa, GUa, BUa, . . . , that is,a U pixel row corresponding to the R pixel illustrated in FIG. 2.

FIGS. 31A and 31B illustrate an NA configuration of phase differencepixels for detecting a focal position by detecting phase difference withrespect to left, upper, right, and lower directions, according to anembodiment. The NA configuration is made in a direction converse to theMA configuration.

FIGS. 32A and 32B illustrate an MB configuration of phase differencepixels for detecting a focal direction by detecting phase differencewith respect to right, upper, left, and lower directions, according toan embodiment. The MB configuration has an aperture ratio of more than50%, an optical aperture of which includes an optical axis of an imaginglens.

FIGS. 33A and 33B illustrate an NB configuration of phase differencepixels for detecting a focal direction by detecting phase differencewith respect to left, upper, right, and lower directions, according toan embodiment. The NB configuration is made in a direction converse tothe MB configuration.

FIG. 34 illustrates a combined configuration of the phase differencepixels of FIGS. 30A, 30B, 31A, 31B, 32A, 32B, 33A, and 33B, according toan embodiment.

The configuration of FIG. 34 is for multifocal point detection at nineareas. Referring to FIG. 34, HAs, VAs, and HVAs are arranged at acentral area and further arranged on upper, lower, left, and right sidesof the central area, and MAs and NAs for focal position detection arearranged in an inclined direction at four areas on left, right, upper,and lower directions of the central area. A detection direction of phasedifference information is set in a concentric circle direction withrespect to an optical axis of an imaging lens. HBs used to detect afocal direction in a horizontal direction are arranged around thecentral area, and MBs and NBs are arranged in an inclined direction onupper and lower sides of left and right slopes. In addition, VBs used todetect a focal direction in a vertical direction are arranged onoutermost sides of the imaging device.

As described above, according to the one or more embodiments, an imagingdevice may perform phase difference detection using the entire surfaceof a captured image without addition of pixels.

All references, including publications, patent applications, andpatents, cited herein are hereby incorporated by reference to the sameextent as if each reference were individually and specifically indicatedto be incorporated by reference and were set forth in its entiretyherein.

For the purposes of promoting an understanding of the principles of theinvention, reference has been made to the embodiments illustrated in thedrawings, and specific language has been used to describe theseembodiments. However, no limitation of the scope of the invention isintended by this specific language, and the invention should beconstrued to encompass all embodiments that would normally occur to oneof ordinary skill in the art. The terminology used herein is for thepurpose of describing the particular embodiments and is not intended tobe limiting of exemplary embodiments of the invention. In thedescription of the embodiments, certain detailed explanations of relatedart are omitted when it is deemed that they may unnecessarily obscurethe essence of the invention.

The apparatus described herein may comprise a processor, a memory forstoring program data to be executed by the processor, a permanentstorage such as a disk drive, a communications port for handlingcommunications with external devices, and user interface devices,including a display, touch panel, keys, buttons, etc. When softwaremodules are involved, these software modules may be stored as programinstructions or computer readable code executable by the processor on anon-transitory computer-readable media such as magnetic storage media(e.g., magnetic tapes, hard disks, floppy disks), optical recordingmedia (e.g., CD-ROMs, Digital Versatile Discs (DVDs), etc.), and solidstate memory (e.g., random-access memory (RAM), read-only memory (ROM),static random-access memory (SRAM), electrically erasable programmableread-only memory (EEPROM), flash memory, thumb drives, etc.). Thecomputer readable recording media may also be distributed over networkcoupled computer systems so that the computer readable code is storedand executed in a distributed fashion. This computer readable recordingmedia may be read by the computer, stored in the memory, and executed bythe processor.

Also, using the disclosure herein, programmers of ordinary skill in theart to which the invention pertains may easily implement functionalprograms, codes, and code segments for making and using the invention.

The invention may be described in terms of functional block componentsand various processing steps. Such functional blocks may be realized byany number of hardware and/or software components configured to performthe specified functions. For example, the invention may employ variousintegrated circuit components, e.g., memory elements, processingelements, logic elements, look-up tables, and the like, which may carryout a variety of functions under the control of one or moremicroprocessors or other control devices. Similarly, where the elementsof the invention are implemented using software programming or softwareelements, the invention may be implemented with any programming orscripting language such as C, C++, Java, assembler, or the like, withthe various algorithms being implemented with any combination of datastructures, objects, processes, routines or other programming elements.Functional aspects may be implemented in algorithms that execute on oneor more processors. Furthermore, the invention may employ any number ofconventional techniques for electronics configuration, signal processingand/or control, data processing and the like. Finally, the steps of allmethods described herein may be performed in any suitable order unlessotherwise indicated herein or otherwise clearly contradicted by context.

For the sake of brevity, conventional electronics, control systems,software development and other functional aspects of the systems (andcomponents of the individual operating components of the systems) maynot be described in detail. Furthermore, the connecting lines, orconnectors shown in the various figures presented are intended torepresent exemplary functional relationships and/or physical or logicalcouplings between the various elements. It should be noted that manyalternative or additional functional relationships, physical connectionsor logical connections may be present in a practical device. The words“mechanism”, “element”, “means”, and “construction” are used broadly andare not limited to mechanical or physical embodiments, but may includesoftware routines in conjunction with processors, etc.

The use of any and all examples, or exemplary language (e.g., “such as”)provided herein, is intended merely to better illuminate the inventionand does not pose a limitation on the scope of the invention unlessotherwise claimed. Numerous modifications and adaptations will bereadily apparent to those of ordinary skill in this art withoutdeparting from the spirit and scope of the invention as defined by thefollowing claims. Therefore, the scope of the invention is defined notby the detailed description of the invention but by the followingclaims, and all differences within the scope will be construed as beingincluded in the invention.

No item or component is essential to the practice of the inventionunless the element is specifically described as “essential” or“critical”. It will also be recognized that the terms “comprises,”“comprising,” “includes,” “including,” “has,” and “having,” as usedherein, are specifically intended to be read as open-ended terms of art.The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the invention (especially in the context of thefollowing claims) are to be construed to cover both the singular and theplural, unless the context clearly indicates otherwise. In addition, itshould be understood that although the terms “first,” “second,” etc. maybe used herein to describe various elements, these elements should notbe limited by these terms, which are only used to distinguish oneelement from another. Furthermore, recitation of ranges of values hereinare merely intended to serve as a shorthand method of referringindividually to each separate value falling within the range, unlessotherwise indicated herein, and each separate value is incorporated intothe specification as if it were individually recited herein.

What is claimed is:
 1. An imaging device configured to receive an imageformed by an optical system, the imaging device comprising pixels thatare two-dimensionally arranged, each of the pixels comprising: a microlens; a photoelectric conversion unit positioned below the micro lens;and an optical aperture disposed between the micro lens and thephotoelectric conversion unit and that is eccentric with respect to anoptical axis of the micro lens, wherein all pixels of the imaging deviceoutput a signal for obtaining focal point information and comprise firstpixels and second pixels; wherein each of the first pixels has a firstaperture ratio, a first optical aperture corresponding to the firstaperture ratio and does not include the optical axis, and wherein eachof the second pixels has a second aperture ratio that is greater thanthe first aperture ratio, a second optical aperture corresponding to thesecond aperture ratio and includes the optical axis.
 2. The imagingdevice of claim 1, wherein the optical aperture comprises a lightshielding mask.
 3. The imaging device of claim 1, wherein the opticalaperture is formed by eccentrically positioning a wire layer of each ofthe pixels.
 4. The imaging device of claim 1, wherein the opticalaperture of each of the first pixels either does not contact the opticalaxis of the micro lens or contacts but does not include the opticalaxis.
 5. The imaging device of claim 1, wherein each of the pixelscomprises a first, second, or third color filter, and each of the secondcolor filter is disposed in a first pixel having the first apertureratio, and each of the first and third color filters is disposed in asecond pixel having the second aperture ratio that is greater than thefirst aperture ratio.
 6. The imaging device of claim 5, wherein thefirst, second, and third color filters are red (R), green (G), and blue(B) color filters.
 7. The imaging device of claim 6, wherein the G colorfilter is the second color filter, and the R and B color filters are thefirst and third color filters.
 8. The imaging device of claim 5, whereinthe first, second, or third color filters are cyan (C), magenta (M), andyellow (Y) color filters.
 9. The imaging device of claim 1, wherein theoptical aperture is eccentrically formed in horizontal and verticaldirections.
 10. The imaging device of claim 1, wherein the opticalaperture is eccentrically formed in an inclined direction and in adirection converse to the inclined direction.
 11. The imaging device ofclaim 1, wherein the optical aperture comprises a plurality of eccentricoptical apertures to form a full-aperture to use with different lenses.12. The imaging device of claim 1, wherein a focal point detection areahaving the first aperture ratio is arranged at a plurality of positionsincluding a center of the imaging device, and a focal directiondetection area is arranged at a position other than the focal pointdetection area.